My plan is to build a ROV with a frame similar to Steve’s Stinger Retrofit. It will be propelled with two 1100 gph bilge motors fitted with 2” propellers for ahead and reverse, one for horizontal movement and one for vertical.
My idea is to have an onboard battery. Is it possible to have a sealed lead acid battery in a wax filled box? The battery gives 10 Ah and weighs 3.3 kg (7.3 pounds). The dimensions are: 151 x 65 x 112 mm (Abt 5” x 2½” x 4½”)
Is it to heavy? Will the ROV be possible to move in the water? Is 10 Ah sufficient or will the battery “run dry” in a short time?
Any comments will be highly appreciated!
On board battery
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Silver dollar
- Posts: 75
- Joined: Feb 20th, 2011, 3:03 pm
- Location: Munkedal, Sweden
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SoakedinVancouver
- Posts: 117
- Joined: Dec 31st, 2010, 9:38 pm
Re: On board battery
1. Big motor + big props = big power requirements. Do you really need these capabilities?
2. Gas-tight enclosure + (charging)/discharging batteries @ high current = bomb capabilities, due to accumulation of hydrogen gas. Yeah, you still need an eventual proper mix of hydrogen and oxygen, plus a source of ignition, but really, can you handle the risks?
3. Weight, speed and power kinda form a triangle, where each affects the others, i.e., you want speed, therefore you need power but this will bring in more weight. Slow down, with the same weight, you will have power reserves.
So, to go back to 1. Are you sure you have properly identified your power requirements? 2. Is an umbilical such a limitation in your application?
2. Gas-tight enclosure + (charging)/discharging batteries @ high current = bomb capabilities, due to accumulation of hydrogen gas. Yeah, you still need an eventual proper mix of hydrogen and oxygen, plus a source of ignition, but really, can you handle the risks?
3. Weight, speed and power kinda form a triangle, where each affects the others, i.e., you want speed, therefore you need power but this will bring in more weight. Slow down, with the same weight, you will have power reserves.
So, to go back to 1. Are you sure you have properly identified your power requirements? 2. Is an umbilical such a limitation in your application?
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ponynicker53
- Posts: 7
- Joined: Mar 6th, 2011, 4:46 pm
Re: On board battery
I use led-acid onboard batteries. Two 12-v to to exact. As for weight, not a problem. Infact, quite a benefit because I only needed to add 3 kg ballast weight.
As for explosion potential, yes, it is a risk. Ideally, the hydrogen released from the half-cell reaction of the battery will be in an aqueous form in the battery. However, on the chance that some of it vaporizes into the sub's chamber, I have a silver manganese dioxide absorber inside which will bind free hydrogen radicals. I also have some dessicants in there to absorb any extra humidity, to prevent rapid oxidation of battery terminals and electronic components inside the chamber.
As for explosion potential, yes, it is a risk. Ideally, the hydrogen released from the half-cell reaction of the battery will be in an aqueous form in the battery. However, on the chance that some of it vaporizes into the sub's chamber, I have a silver manganese dioxide absorber inside which will bind free hydrogen radicals. I also have some dessicants in there to absorb any extra humidity, to prevent rapid oxidation of battery terminals and electronic components inside the chamber.
Re: On board battery
What size battey are you using? I have thinking about the same, my plan is to use a pvc pipe for battery housing, maybe 4".